title: Extraprostatic extension into periprostatic fat is a more important determinant of prostate cancer recurrence than an invasive phenotype.
abstract: OBJECTIVE
  Although micrometastasis development correlates closely with the depth of invasion of many tumor types, it is unclear whether invasion into but not through the prostatic pseudocapsule has a negative impact on prognosis, similar to extraprostatic extension. We defined the impact of pseudocapsular invasion on the risk of post-prostatectomy biochemical recurrence.
  
  
  METHODS
  Patients with pT2-3a prostate cancer were identified from a prospectively recorded database. Those with pT2 disease were categorized according to pseudocapsular invasion presence or absence. The impact of pseudocapsular invasion on biochemical recurrence was determined by univariable and multivariable Cox regression analysis.
  
  
  RESULTS
  In a cohort of 1,338 patients we identified 595 with organ confined cancer positive for pseudocapsular invasion. Compared to tumors without evidence of invasion, pseudocapsular invasion was positively associated with higher Gleason grade and tumor volume (1.2 vs 1.9 cc, each p<0.001). On univariable analysis there was no difference in biochemical recurrence-free survival between patients with vs without pseudocapsular invasion, although those with extraprostatic extension had significantly lower biochemical recurrence-free survival (p<0.001). This was confirmed on multivariable analysis, which revealed that extraprostatic extension was a significant independent predictor of biochemical recurrence (HR 1.53, p=0.018). The presence of pseudocapsular invasion had no effect (HR 0.81, p=0.33).
  
  
  CONCLUSIONS
  Pseudocapsular invasion is not a pathological feature associated with an adverse outcome after prostatectomy. Thus, the depth of tumor invasion is not a continuum of risk and access to periprostatic adipose tissue is a more important determinant of disease behavior than an invasive phenotype.
authors.affiliation: Departments of Urology and Surgery, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia; Australian Prostate Cancer Centre Epworth, Richmond, Victoria, Australia; TissuPath Pty Ltd, Hawthorn, Victoria, Australia; Department of Urology, Box Hill Hospital, Box Hill, Victoria, Australia. Electronic address: jadakapoor28@live.com.
authors.forename: Jada
authors.initials: J
authors.lastname: Kapoor
authors.forename: Benjamin
authors.initials: B
authors.lastname: Namdarian
authors.forename: John
authors.initials: J
authors.lastname: Pedersen
authors.forename: Chris
authors.initials: C
authors.lastname: Hovens
authors.forename: Daniel
authors.initials: D
authors.lastname: Moon
authors.forename: Justin
authors.initials: J
authors.lastname: Peters
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Costello
authors.forename: Paul
authors.initials: P
authors.lastname: Ruljancich
authors.forename: Niall M
authors.initials: NM
authors.lastname: Corcoran
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D010641:Phenotype; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000235:genetics / Q000473:pathology*
keywords: EPE; OC; PCI; PSA; extraprostatic extension; local; neoplasm invasiveness; neoplasm recurrence; organ confined; prostate; prostate specific antigen; prostate-specific antigen; prostatic neoplasms; pseudocapsular invasion